In the monolithic integration of high-accuracy current dividers with current sources for the large-scale production of monolithic integrated solid-state circuits there exists the difficulty of the process variations occurring in the manufacture of the current sources which, as is well known, can be realized in the form of collector-emitter sections of bipolar transistors of a so-called current bank, with the base electrodes being placed on a common potential. This difficulty, in the case of a monolithic integrated digital-to-analog converter (hereinafter briefly referred to as a "DAC") for a 14-bit dual number, with bipolar transistors, of the type as described in "Electronics" of June 16, 1983, pp. 130 to 134, and in "Electronic Components and Applications," Vol. 2, No. 4 (August 1980), pp. 235 to 241, has been overcome by using an integrated current divider, chiefly in that the currents of a plurality of current sources, with the aid of a shift register, are cyclically and rotatingly switched to three current paths of which the first and the second ones receive half the current of the third current. By cascading a plurality of such current dividers it is possible to obtain a highly accurate monolithic integrated DAC.
The present invention likewise makes use of this principle of dynamic "element matching" without, however, employing the above-mentioned current divider of the conventional DAC. Since that converter employs cascaded current dividers, one RC filter circuit with capacitors connected from the outside is required for each of the current dividers.
An object of the invention is to provide a monolithic integrable DAC which does not require any RC filter circuits and which, in particular, is capable of being manufactured in metal-oxide-semiconductor (MOS) technology without requiring a supply voltage substantially higher than 5 V. When the conventional arrangement is manufactured in MOS technology, and owing to the cascading of the dividers, there is required a supply voltage of more than 25 V.